This invention relates to casting shake-out units used to separate or remove sand from castings, and in particular to a liner which forms the inner surface of the shake-out unit.
In the formation of a tumbling mill, such as a casting shake-out unit, rotary separator, media drum, material drier, lump crusher reclaimer, blending drum, sand screen, or the like, it is desirable to form the inner surface of the mill from segments. Thus, when individual segments wear out, they can be replaced easily and rapidly without the need to incur a significant amount of downtime or expense. An example of a shake-out unit having a segmented inner surface or lining is disclosed in U.S. Pat. No. 3,998,262, which is assigned to the same assignee as the present invention, and which is incorporated herein by reference. As set forth in that patent, the inner cylinder forming the inner surface of the unit is formed from a series of interconnected modular components. The operation of that unit, for its intended purpose, has performed highly satisfactorily. However, it has one minor draw back. When the casting shake-out unit is operated continuously, the wear on the components causes the components or segments to gradually loosen. This requires a retightening of the entire formed inner surface.
It is desirable to enable the machine to operate for a longer period of time before the segments begin to loosen and separate. In U.S. Pat. No. 4,502,808, also assigned to the same assignee as the present invention and which is also incorporated herein by reference, the side edges of the segments were grooved to define a channel between neighboring segments. A pin or bar, which is shaped to have an angle formed therein, is inserted in the channel. In a completed lining, the bars tend to urge the segments apart, thus creating a tight fit in the completed cylindrical lining. This too has worked exceedingly well for its intended purpose, and has enable the shake-out unit to be operated for a longer period of time before the machine had to be shut down to tighten the segments together. However, if a pin wears down, a segment can fall out of the lining. This is obviously undesirable.